An official memorial service held in Melbourne today will mourn the 298 people killed when flight MH17 was shot down over eastern Ukraine last month, including 38 Australian citizens and residents.

In a pre-recorded message, Prime Minister Tony Abbott paid respect to the victims of the tragedy: 'Today is a national day of mourning. We will pause and we will remember the 298 innocent people who died on flight MH17. We will give thanks for their lives and we will pray for their loved ones.'

Prime Minister Abbott said flags would be lowered across the country. National leaders, Dutch and Malaysian ambassadors and families of the victims will be in attendance at the memorial service.

Professor Beverley Raphael from the ANU and University of Western Sydney has worked with the victims of many recent tragedies. She told RN Breakfast that today would be a very significant day for the families of those who died.

'A national commemoration is very important because it tells people the government and the country are offering support and recognising the horrific losses that they've suffered and the trauma associated with it,' she said.

Raphael said that while anger was a normal emotion experienced with grief, holding on to anger and bitterness for an extended period of time can get in the way of properly paying tribute to and grieving for loved ones.

'We know from a vast body of research now that when a disaster is an act of man, as it were... that particular factor adds an enormous burden of trauma and anger and unresolved grief that people struggle to handle for a quite a period of time.'